Previous research has shown that children with disruptive behavior problems tend to have poor relations with their peers and that these poor peer relations place the children at risk for later adjustment problems. However, although researchers have specified behaviors that account for disruptive children's tendency to become rejected by peers, such as biases towards attributing hostile intent to others, researchers have not yet specified internal mechanisms that account for children's biases and deficits. This proposed study will examine the possibility that children's perspective-taking abilities affect their social competence with peers. Specifically, the study will examine links between young children's cognitive and affective perspective-taking abilities, their symbolic play, and their observed behaviors with peers. The long-term objectives of this study are two-fold. First, if children's perspective-taking abilities at preschool age can be linked to problems in relations with peers, this might provide researchers with a method for early identification of children at risk for poor peer relations. Secondly, the proposed study will examine the links between symbolic play and both perspective-taking and social competence in children. If symbolic play is related to social competence in children, this would provide researchers with a cost- effective, naturalistic, and potentially universal mode of intervention for preschoolers at risk for behavior problems. Understanding the links between perspective-taking, symbolic play, and children's social competence with peers will allow for the development of more effective prevention and intervention programs.